Programmable timer

ABSTRACT

A programmable timer to initiate an electrical response or subsequent operation a time period after receipt of a pair of signals where the time period is dependent upon a variable function of the time interval between the signals and the time interval itself using a pair of relatively movable contact members.

United States Patent [72] Inventor Eugene W. Kenderdine Sandie Park, N. Mex.

21 1 App]. No. 773,835

[22] Filed Nov. 6, 1968 [45] Patented Oct. 19, 1971 [73] Assignee The United States of America as represented by the United States Atomic Energy Commission [54] PROGRAMMABLE TIMER 10 Claims, 7 Drawing Figs.

[52] U.S. Cl 307/139, 200/46, 200/47 [51] Int. Cl. H0lh 3/00 [50] Field oiSearch 367/139, 140, 112, 133; 200/6l.42,46, 47

[56] References Cited UNITED STATES PATENTS 2,594,716 4/1952 Bailey 200/46 X Primary Examiner-Herman J. Hohauser Attorney-Roland A. Anderson ABSTRACT: A programmable timer to initiate an electrical response or subsequent operation a time period after receipt of a pair of signals where the time period is dependent upon a variable function of the time interval between the signals and the time interval itself using a pair of relatively movable contact members.

TRANSDUCER SXGNAL PATENIEnuU 19 Ian 3, 6 1 4. 46 5 SHEET 10F. 2

44 TRANSDUCER f SIGNAL INVENTOR.

Eugene M Kenderd/he QLWM Attorney BACKGROUND OF IN VENTlON There are many applications where the duration of a particular operation or step in a process may be dependent on the duration of another previously occurring or simultaneous operation or step. Such a timing function may be difficult to obtain in automated operations, especially where the timing base operation, i.e. the previous occurring or simultaneous operation, may be of variable duration or period. This is particularly troublesome in circumstances where a subsequent operation must be extended or curtailed if a previous timing base operation malfunctions or fails. For instance, in a multistage rocket, malfunction of an initial stage by premature termination or prolongation of firing may require a longer or shorter firing period of a succeeding stage, depending upon the particular malfunction.

Timers for achieving such timing functions are preferably compact and simple and should be highly reliable. Further, such timers should be capable of being adapted to many different timing functions.

SUMMARY OF INVENTION In view of the limitations as noted above, it is an object of this invention to provide a timer which may initiate an electrical response or some other operation a preselected varying time period after receipt of a pair of signals.

It is a further object of this invention to provide a timer which may initiate an electrical response after a time period which is a function of the time interval between a pair of signals.

It is a further object of this invention to provide a variable delay timer which is both compact and has a high degree of reliability.

Various other objects and advantages will appear from the following description of one embodiment of the invention, and the most novel features will be particularly pointed out hereinafter in connection with the appended claims.

The invention comprises a timer which may be programmed to provide an electrical response after any desired time period subsequent to receipt of a pair of signals where the time period is dependent upon a function of the time interval between the signals and the time interval itself, including a plurality of relatively movable contacts, what may be a printed circuit and an electrical contact sequentially movable with respect to each other along separate coordinates of said circuit at preset speeds in response to said signals, wherein said electrical contact or contacts effects a circuit closure upon reaching a predetermined position after receipt of the second signal.

DESCRIPTION OF DRAWINGS The present invention is illustrated in the accompanying drawings wherein;

FIG. 1 is a diagrammatic view partially in perspective of a timer device showing the principles of this invention;

FIG. 2 is a simplified, perspective view of an embodiment of this invention;

FIG. 3 is a fragmentary view of a modified form of the device shown in FIG. 2;

FIG. 4 is a graph showing various timing functions which may be used in the devices shown in FIGS. 1 and 2;

FIG. 5 is a graph of the resultant timing periods which may be provided by the timing functions of FIG. 4;

FIG. 6 is an elevation view of various printed circuit patterns which may be used in the device of FIG. 2 to provide the timing functions and periods shown in FIGS. 4 and 5; and

FIG. 7 is partially cutaway, fragmentary elevation view of a mainspring protective and torque selector mechanism which may be used with this invention.

DETAILED osscrumou The programmed timing function of the present invention may be obtained by the apparatus shown in FIG. 1. As shown, the apparatus may include a suitable contact element or board iii having on one surface thereof a first portion 12 electrically isolated from a second portion 14 along a boundary or dividing line 16 having some desired pattern or outline depending on the particular timing function requirements. The boundary between portions 32 and 14 may be formed by a printed circuit type of conductive or insulative pattern applied to one or both of portions 12 and 14. For example, if contact element 10 is made of some electrically conductive material such as aluminum or copper, portion 14 may be entirely covered with an insulative coating 18 (shown with exaggerated thickness for purpose of illustration) up to boundary 16. Conversely, contact element 10 may be made of an insulative material and both portions 12 and 14 covered with a conductive coating with an insulative gap therebetween along boundary 16. Any number of combinations of insulative and conductive coatings and plate materials may be used as will become apparent from the further description of the invention.

Boundary 16 may have any desired two-dimensional configuration or pattern depending on the desired timing function as will be described more fully with respect to FIGS. 4 and 5. Boundary 16 may be varied linearly or nonlinearly in an increasing or decreasing manner or maintained constant along the y axis of contact element 10. In the embodiment shown, boundary in begins at some intermediate position 200 along the x axis of contact element 10 increasing nonlinearly to position 26b. Boundary 16 then decreases linearly to position 20c continues constant to position 20d, increases linearly to position 2% and then decreases linearly to position 20f.

Contact element 10 may be mounted so as to be movable along one dimension or axis thereof (the y axis as shown) by any conventional means such as guideway 22 and a motor 24 driven longitudinal drive system such as rack and pinion gear 26. Motor 24 may be any conventional constant speed electrically or mechanically actuated motor means such as an escapement regulated, mainspring drive motor or a DC or AC electrical motor. Rack and pinion gear 26 and contact ele ment 10 are shown at some position which may be the initial starting position of the timer or an intermediate or final position after motor 24 has driven contact element 10 in the direction of arrow 28, depending on the desired timing function. For purposes of illustration, the position shown will be considered an intermediate position of rack and pinion gear 26 after receipt of the required signal pulses or indicia.

A suitable electrical connection may be made to portion 12 of contact element 10 which maintains electrical contact therewith in any position and during any movement of contact element 10. For example, a sliding contact (not shown) may be positioned so as to make contact with an edge of contact element 10, or a fixed contact 30 may be fastened or attached directly thereto.

A sliding contact 32 may be suitably mounted so as to be movable along another dimension or axis of contact element 10 in the direction of arrow 34 different from the movement of the plate itself, such as the x axis. Such contact movement may be provided by a motor 36 driven longitudinal drive system 38 through an arm having sliding contact 32 attached to an extremity thereof. Ann 40 and contact 32 are shown for purpose of illustration at some intermediate position on portion M of contact element 10 as determinded by the previous movement of contact element it) by motor 24 in the direction of arrow 28 and the movement of arm 40 by motor 36 in the direction of arrow 34. Generally, aRm 40 may be positioned initially along one edge or side of portion 14 opposite boundary 36 adjacent the beginning of the timing function near position Zita.

A utilization device 42, such as a control circuit or mechanism requiring a timing signal may be connected through arm 40 between contact 32 and contact 30. In this embodiment, contacts 30 and 32 reflect an open circuit condition to device 42 until such time as contact 32 crosses boundary l6 and contacts portion 12 of contact element iii.

The movement of contact element 110 and arm 40 may be controlled by suitable control circuits or mechanisms which actuate motors 24 and 36 in the desired sequence of operation as determined by some external control signals or indicia. in this invention, it is desired that the closing of contacts 30 and 32 through portion 12 of contact element It) occur some variable time period after receipt of a pair of control signals or other indicia where the time period is a function of the time interval between the control signals. A suitable control circuit or mechanism may include a transducer 44 which converts the control signals, such as an electrical pulse, radio signal or other physical event, into electrical or mechanical energy and a switching network 46 which transmits this energy to the appropriate motor 24 and then motor 36 in sequence. A first control signal actuates motor 24 while a second control signal deactivates motor 24 and actuates motor 36. Additional means (not shown) may be provided with transducer 44 and network 46 to reset contact element and arm 40 in an initial position after completion of a timing cycle for repeating the timing sequence by reversing the direction of rotation of motors 24 and 36. Transducer 44 may be a radio network for receiving radio signals and converting them to pulses or other usable electrical energy while network 46 may be conven tional electrical or electromechanical logic switching circuits. Transducer 44 may also be a conventional piezoelectric or the like transducer for responding to any desired physical phenomena such as vibrations or pressure waves which represent the control signals.

In the embodiment shown, when an appropriate first control signal is received by transducer 44, driving energy is supplied through network 46 to motor 24 initiating movement of contact element 10 along guideway 22 in the direction of arrow 28. As contact element 10 moves in this direction, contact 32, which is held stationary by arm 40, is simultaneously moved with respect to boundary 16 along portion 14. Upon receipt of a second control signal by transducer 44, the driving energy may be switched by network 46 from motor 24 to motor 36, thus stopping contact element 10 and driving arm 40 and contact 32 in the direction of arrow 34. When contact 32 crosses boundary l6 and contacts portion 12, a circuit is completed between contacts 30 and 32 to utilization device 42. The complete path followed by contact 32 may be seen by dotted line and arrows 48. The time delay between receipt of the second control signal and closing of the circuit between contacts 30 and 32 is dependent on the position of arm 46 with respect to boundary 16 after contact element 10 reaches its final position, the configuration of boundary 16, the speed of motor 36 and the gear ratio of drive system 38. The distance to boundary 16, and the time delay dependent thereon, varies as the length of time interval between control signals. The final position of contact element 10 is dependent on the time interval between control signals, the speed of motor 24 and the gear ratio of drive system 26. Thus, the total time period between the first control signal and the closing of contacts 30 and 32 is dependent on a function of the time interval between control signals. It will be apparent that an additional variable may be included in the timing period by varying the speed of motors 24 and 36.

Provision may be made for a possible control signal failure by extending portion 12 across the initial path of contact 32 with an appropriate boundary 16, as shown, so that if only one control signal is received, contact closure may still occur and thus prevent complete failure of the timing system. When contact closure occurs, utilization device 42 may feed back a signal to network 46 and transducer 44 to stop movement of arm 40 and to reset arm 40 and contact element 16 to a desired initial position.

In the embodiment of the invention illustrated in F IG. 2, the two-dimensional printed circuit" type boundary 50 is applied to a suitable circular contact element or board 52 using a polar coordinate system about a central axis of rotation. Boundary 56 comprises an insulative coating or gap between a first conductive portion 54 about the central part of beard 52 and a second conductive portion 56 about the periphery of board 52. Electrical circuit closure for some external utilization device (not shown), such as described above with respect to FIG. 1, may be achieved between a sliding contact 58 which is fixed in a position along the periphery of board 52 in contact with second portion 56 and moving contact 60 which is initially in contact with first portion 54 adjacent the center of board 52. Board 52, which is affixed to a central shaft 62, may be driven through a desired angular coordinate via shaft 62 and drive shaft 63 by motor 64 and a clutch and drive transmission 66. Moving contact 60, which is attached to a rotata ble arm 63, may be driven along the radial coordinate of the polar coordinate system by cam follower 70 and a cam 72 rotatably driven through clutch and drive transmission 66 by motor 64. Board 52 and moving contact 60 may be separately and sequentially driven through clutch and drive transmission 66 by a suitable gear selector system 74. Gear selector 74 may be controlled by an appropriate control signal transducer apparatus 76.

Motor 64 may be any conventional constant-speed drive motor or system of the same type as described above with respect to motors 24 and 36 in FIG. 1. Clutch and drive transmission 66 may be any conventional mechanism which may selectively couple drive shaft 63 to shaft 62 and then to cam 72 upon receipt of the proper pair of control signals. A particularly suitable mechanism is an epicyclic gear including one or more planet gears 78 coupled to drive shaft 63, a sun gear Si) attached to shaft 62 and a ring gear 82 coupled by a tubular shaft 84 to earn 72. When motor 64 turns shaft 63 and planet gears 73, sun gear and ring gear 82 may rotate. If a restraint is applied to either sun gear 80 or ring gear 82, the unrestrained gear may rotate. If both gears are restrained, motor 64 is also restrained from turning shaft 63.

Suitable restraints may be applied selectively to the appropriate gears, and consequently to cam 72 and board 52, by gear selector 74. The gear selector mechanism may be adapted to engage, with spring-biased rotatable arms 86, 88 and 96, suitably positioned restraints on the respective gears on their associated parts such as ear or tab 92 on ring gear 82 or teeth 94 extending directly from board 52 or a separate serrated braking disc fastened to shaft 62, as shown. Arms 86 and 88 are rotatably fixed to each other by a common shaft. Each arm includes a finger or pointer to engage the appropriate restraint. Arms 88 and 96 may include cam follower portions which engage cams 89 and 91 associated with control signal transducer 76. In the initial position of the timing apparatus, arm 86 may engage ear Q2 while arm engages teeth 94, thus restraining both cam 72 and board 52.

Transducer 76 may convert the necessary control signals to a mechanical movement which may then rotate arms 86, 88 and 96 in the proper sequence and direction to release and/or restrain cam 72 and board 52 respectively and provide the desired timing function. To effect this conversion, transducer 76 may include a rotary solenoid 96 coupled through pawl and ratchet 98 and shaft 166 to earns 89 and 91. Solenoid 96 may be selected so as to rotate a prescribed angle, such as about 30 for each control signal or control signal pulse received. Cams 89 and 9ll each include a single stepped cam surface with the steps angularly displaced from each other an angle slightly less than a single pulsed rotation of solenoid 96. Cams 89 and 911 are shown in their initial position at the start of a timing cycle.

Boundary 50 may have any desired polar coordinate configuration as determined by the required timing function and will be described more fully with respect to FIGS. 4, 5 and 6. Cam 72 may have any desired cam surface shape which when combined with boundary 5!) will provide the required timing function. For instance, the cam surface may be in the form of an increasing Archemedean spiral, as shown, or decreasing spiral or include combinations of increasing and decreasing spirals or curves. An Archemedean spiral shaped cam surface rotated at a constant speed effects uniform rate of change in radius of moving contact 69 across board 52.

Upon receipt of a first control signal pulse, solenoid 96 may rotate the prescribed angle to turn earns 89 and 91 to a position where the cam follower portion of arm 96 has passed the cam step of cam 91. Spring-biased arm 99 may then rotate about its axis of rotation and release its finger or pointer from engagement with teeth 94 and permit rotation of board 52 by motor 64 through planet gears 78 and sun gear 80. As motor 64 drives board 52 at a preset rate of rotation from its initial position, contact 58 and movable contact 69 remain in the same initial fixed position shown with respect to the other members of the timing apparatus but at a different radial position with respect to boundary 50 dependent on the angle of rotation of board 52. Upon receipt of a second control signal pulse, solenoid 96 may rotate the prescribed angle beyond its first rotation to turn cams 89 and 91 to position where the cam follower portion of arm 88 has passed the cam step of cam 89. Spring-biased arm 88 may then rotate about its axis of rotation to engage its finger or pointer with teeth 94 and restrain beard 52 from further movement. Simultaneously, arm 86 may rotate about the same axis of rotation to release its finger or pointer from engagement with tab 92 and permit rotation of cam 72 by motor 64 through planet gears 78 and ring gear 82. As motor 64 drives cam 72 at a preset rate of rotation from its initial position, contact 60 may be slideably moved about its axis of rotation, generally along a radius of board 52, until ring gear 82 or its associated members reach some restraint or solenoid 96 rotates cams 89 and 91 to the initial position where am 86 engages tab 92 and arm 90 engages teeth 94. After some period of time dependent on the configuration of boundary 5t and the rotation of board 52 determined by the time interval between control signal pulses, contact 60 may cross boundary 50 contacting second portion 56 and closing a circuit with contact 58.

The timing apparatus may be reset to its initial position for additional timing operations by reversing cam 72 and board 52 to their initial positions and, where motor 64 is an escapement regulated mainspring drive motor, also rewinding the mainspring of motor 64, or continuing the rotation thereof to their initial positions while resetting gear selector 74 and signal transducer 76.

FIG. 3 shows a modified gear selector which may be utilized in place of the gear selector shown in FIG. 2. In this embodiment spring-biased arms 86, 88, and 90 may be directly attached through shaft 102 and all arms rotated about the same axis of rotation. Arm 99 may include a cam follower portion adjacent a single cam 104 driven by solenoid 96 and having a pair of decreasing amplitude cam steps 106 and 108. As cam 104 turns and arm 90 follows cam steps 1106 and 198, arms 86, 88 and 90 rotate in the directions of the arrows to provide the desired sequence of operation. It should be noted that the distance between the finger of arm 88 and teeth 94 and the length of the finger of arm 86 and tab 92 should be chosen in the initial position to permit the rotation of arms 88 and 86 by cam step 196 without engaging teeth 94 and disengaging tab 92 respectively.

FIGS. 4, 5 and 6 illustrate various timing functions which may be achieved by the devices shown in FIGS. 1 and 2 and the configurations of the printed circuit boundaries needed to provide these functions. In FIG. 4, curves 110, i112 and 114 illustrate three examples of timing functions (f(At) as time changes in incremental steps (At). By way of illustration, curve 112 will be described in detail and includes a linearly increasing portion ll6, a step increase portion 118, a constantlevel portion I20, a first linearly decreasing portion 122, a second constant-level portion R24 and a second linearly decreasing portion 126.

FIG. 5 shows the total resultant time period (T) by curves 110a. Il2a and 1140 provided by the timing apparatus from the time of the first control signal to circuit closure across the printed circuit boundary for the correspondingly numbered timing functions of FIG. 5 as the time interval (A!) between control signals increases. The total resultant time period represents the time interval of movement of the printed circuit board along a coordinate of the two-dimensional system added to the time delay required to drive the moving contact across the boundary along the other coordinate (i.e., T swim).

It will be apparent that boundary 16 in FIG. 1 may have the same configuration as the curves shown in FIG. 4 to provide the timing periods shown in FIG. 5. I order to provide these same timing periods in the embodiment of FIG. 2, boundary 50 may have the correspondingly numbered configurations shown in FIG. 6 where each increment of time (At) equals about 45. For example, boundary 50 for the flAt) of curve M2 may include an increasing spiral portion 116b, a step increase portion 11812, a first circular arc portion 120b, a first decreasing spiral portion 122b, a second circular arc portion 124b and a second decreasing arc portion 126b, Since moving contact 60 travels in an are about the axis of rotation of arm 68, the boundary shape may be adjusted to compensate for the increase in contact travel resulting therefrom.

It may be desirable when using an escapement regulated, mainspring drive motor for any of motors 24, 36 and 64 as shown in FIGS. 1 and 2, to provide a mechanism which may prevent overwind and playout of the motor mainspring. Such a mechanism would also permit the selection of a particular portion of the drive torque curve for the mainspring which results in a more constant and predictable driving torque during a timing cycle. Such a mechanism is shown in FIG. 7 in the initial or reset position at the beginning of a timing cycle. The mainspring protective and torque selector mechanism may include a generally F-shaped barrel stop 130 with the upper arm or finger ll31 engaging a slot in a raised cam surface 132 attached to mainspring barrel 134. Barrel stop 130 may rotate about shaft 136 when suitably released from the cam surface slot and driven by toggle spring 138 and one or more of bar 140 and the other arms and projections or surfaces of the barrel stop. Toggle spring 138 rotates about a fixed shaft 142. A suitable drive shaft, such as shaft 63, may be attached to the mainspring arbor (not shown) centrally of mainspring barrel 134 in manner well known in the art. The various arms, projections and surfaces of barrel stop 130 may be driven in the desired sequence by pins 144 and 146 projecting from opposite surfaces of a monitor gear 148 and by pin 152 upwardly projecting from mainspring barrel 134. Gear 148 may be driven by a gear 150 rotatably fixed to shaft 63 at any desired rate of rotation. The initial or reset position may be monitored or sensed through a cam-operated switch 154 associated with monitor gear 158, as shown.

As noted above, shaft 63 may be restrained by gear selector 741. At the same time, barrel stop 130 restrains mainspring barrel 134. When shaft 63 is suitably released and rotated through the timing cycle, the action of pin 144 against bar 140 may rotate barrel stop 130, after some prescribed rotation of gear 148 and time period, from its engagement with the slot in cam 132 of the mainspring barrel. Mainspring barrel 134 is thus free to be rewound in the clockwise direction. The mainspring barrel is normally restrained from unwinding in the counterclockwise direction with conventional ratchet means (not shown). Toggle spring 138 may then further pivot barrel stop to block further rotation of shaft 63 via pin 146 and monitor gear M8. When the spring is rewound, pin 152 and toggle spring 138 in sequence may rotate barrel stop 130 into engagement with the slot in cam 132.

In the mechanism shown in FIG. 7, the winding and unwinding operation is performed using one turn of the mainspring barrel and drive shaft respectively. Additional turns may be achieved by selecting suitable gear ratios between monitor gear MB and gear 150 or with other conventional means.

The timing apparatus of this invention may initiate a response, electrical or otherwise, a preselected time period after receipt of a pair of control signals where the time period is a function of the time interval between the control signals. A

timing function of the time period may be conveniently varied over a wide range by substituting easily made and replaced printed circuit boards or the like having different boundary patterns applied thereto. Such a timing apparatus may be compactly made having a volume of about 3 cubic inches and high reliability.

It will be understood that various changes in the details, materials and arrangements of the parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principles and scope of the invention as expressed in the appended claims.

What is claimed is:

1. A programmable timer for effecting operation of an electric circuit a time period afler receipt of a pair of signals, said time period being dependent upon the time interval between said signals, comprising a contact element including first and second portions electrically isolated from each other, a first electrical contact initially contacting said fist portion, a second electrical contact initially contacting said second portion and electrically isolated from said first contact, means responsive to the first signal of said signal pair for effecting relative movement in a first direction between one of said contacts and said contact element, and means responsive to the second signal of said signal pair for terminating said movement in said first direction and for effecting relative movement in a second direction of one contact with respect to the other contact and between one of said contacts and said contact element to provide electrical closure of said contacts on one of said portions.

2. The timer of claim 1 wherein said first and second portions of said contact elements are electrically isolated from each other across a boundary of predetennined pattern.

3. The timer of claim 2 wherein said means responsive to the first signal drives said contact element along a first coordinate of said contact element.

4. The timer of claim 3 wherein said boundary varies along said first coordinate.

5. The timer of claim 3 wherein said means responsive to the second signal drives said first contact along a second coordinate of said contact element.

6. The timer of claim 5 wherein said means responsive to said signal pair includes an epicyclic gear having motor-driven planet gearing, a sun gear and a ring gear.

'7. The timer of claim 6 wherein said sun gear and ring gear are separately coupled to one of said electrical contacts and said contact element.

8. The timer of claim 7 including means for selectively restraining said sun gear and said ring gear.

9. The device of claim 8 including means for sequentially actuating said restraining means in response to said signal pair.

10. The device of claim 9 wherein said actuating means includes cam surface means and cam follower means coupled to said restraining means. 

1. A programmable timer for effecting operation of an electric circuit a time period after receipt of a pair of signals, said time period being dependent upon the time interval between said signals, comprising a contact element including first and second portions electrically isolated from each other, a first electrical contact initially contacting said fist portion, a second electrical contact initially contacting said second portion and electrically isolated from said first contact, means responsive to the first signal of said signal pair for effecting relative movement in a first direction between one of said contacts and said contact element, and means responsive to the second signal of said signal pair for terminating said movement in said first direction and for effecting relative movement in a second direction of one contact with respect to the other contact and between one of said contacts and said contact element to provide electrical closure of said contacts on one of said portions.
 2. The timer of claim 1 wherein said first and second portions of said contact elements are electrically isolated from each other across a boundary of predetermined pattern.
 3. The timer of claim 2 wherein said means responsive to the first signal drives said contact element along a first coordinate of said contact element.
 4. The timer of claim 3 wherein said boundary varies along said first coordinate.
 5. The timer oF claim 3 wherein said means responsive to the second signal drives said first contact along a second coordinate of said contact element.
 6. The timer of claim 5 wherein said means responsive to said signal pair includes an epicyclic gear having motor-driven planet gearing, a sun gear and a ring gear.
 7. The timer of claim 6 wherein said sun gear and ring gear are separately coupled to one of said electrical contacts and said contact element.
 8. The timer of claim 7 including means for selectively restraining said sun gear and said ring gear.
 9. The device of claim 8 including means for sequentially actuating said restraining means in response to said signal pair.
 10. The device of claim 9 wherein said actuating means includes cam surface means and cam follower means coupled to said restraining means. 